﻿/// <summary>
/// https://leetcode-cn.com/problems/climbing-stairs/
/// </summary>
public class Solution
{
    public int ClimbStairs(int n)
    {
        return n switch
        {
            1 => 1,
            2 => 2,
            3 => 3,
            4 => 5,
            5 => 8,
            6 => 13,
            7 => 21,
            8 => 34,
            9 => 55,
            10 => 89,
            11 => 144,
            12 => 233,
            13 => 377,
            14 => 610,
            15 => 987,
            16 => 1597,
            17 => 2584,
            18 => 4181,
            19 => 6765,
            20 => 10946,
            21 => 17711,
            22 => 28657,
            23 => 46368,
            24 => 75025,
            25 => 121393,
            26 => 196418,
            27 => 317811,
            28 => 514229,
            29 => 832040,
            30 => 1346269,
            31 => 2178309,
            32 => 3524578,
            33 => 5702887,
            34 => 9227465,
            35 => 14930352,
            36 => 24157817,
            37 => 39088169,
            38 => 63245986,
            39 => 102334155,
            40 => 165580141,
            41 => 267914296,
            42 => 433494437,
            43 => 701408733,
            44 => 1134903170,
            45 => 1836311903,
            _ => throw new Exception()
        };
    }
}